1. Field of the Invention
The present invention relates to recordings and reproductions to and from an optical disk using a plural number of optical heads.
2. Description of the Related Art
In the works of editing and sending-out filed information in broadcasting stations or the likes, chances of using optical disks are steadily increasing. In those works using optical disks, there are many advantages such as a high-speed search that is normally difficult by a video tape recorder (VTR). Furthermore, in a disk system in which a plural number of head groups are installed, those plural number of head groups can independently access over the disk plane. Thereby it becomes possible to realize such an operation as to make recordings of input raw materials simultaneously or successively on different several regions on a plane of a single optical disk, or to make simultaneous or successive reproduction and sending out of data which are already recorded on different regions on a plane of a single optical disk. In Tokkai Hei 08-268672 (Japanese Unexamined Patent Publication 263672/1991), a plural number of heads are installed to a single optical disk, and hence a simultaneous multi-input requests is acceptable. In this case, however, to accomplish the recording and reproduction of television video signals it is necessary to keep the synchronization between the synchronization signal of the video signal and the rotation phase of an optical disk, hence it becomes necessary to establish a special devicing to fulfill requests to input and output all the corresponding input signal by those multiple number of sets of heads.